The invention relates to a drive arrangement for a motor vehicle comprising a prime mover such as an IC engine and hydromechanical power branching transmission with at least two hydromechanical transducers. The invention is more particularly concerned with improvements in vehicles for operating regular services which have to keep to some sort of time schedule or timetable as a matter of necessity. The failure of the prime mover itself or of the supply of energy therefor is a serious matter. When this happens the vehicle is then usually fully out of service and has to be replaced. During the time in which it is waiting to be towed away it may well constitute a hinderance to traffic.